Christoph Berg <christoph(dot)berg(at)credativ(dot)de> writes:
> What is still puzzling me is that the customer is repeatedly reporting
> these issues, even after rebooting the system.
Hm. A server restart really ought to clear any problem in this area,
since pg_notify gets reset to starting conditions. Please check into
that more closely. (It might be worth looking at $PGDATA/pg_notify/
after a restart just to verify there are no files there except 0000.)
regards, tom lane